Gestational diabetes mellitus (GDM) is associated to adverse maternal and neonatal outcomes. The aim of this study is to address whether the addition of extra virgin olive oil to the diet of women with GDM improves maternal triglyceridemia and reduces insulin requirement and diagnosis of diabetes at postnatal reclassification.

This study is a randomized trial in which 1200 pregnant women at GDM diagnosis from 16 health care centers will be recruited and randomized in two parallel arms: 1 World Health Organization (WHO)-diet supplemented with 3 tablespoons of Extra Virgin Olive Oil (Intervention Group, n=600); 2. WHO-diet with no Extra Virgin Olive Oil supplementation (Control Group, n=600). Expected results: the investigators expect that the intervention will contribute to improve maternal lipid profile, reduce insulin requirement and reduce maternal diagnosis of diabetes at postpartum reclassification. Thus, this study is expected to identify maternal beneficial effects of this dietary intervention.

Inclusion Criteria:

• GDM (diagnosis criteria of the Latin American Society of Diabetes (ALAD) and Argentine Society of Diabetes (SAD): Fasting plasma glucosa > 100 mg/dl, p75 oral glucose tolerance test-2 h plasma glucose > 140 mg/dl)

Exclusion Criteria:

• Multiple pregnancy
• Pregestational diabetes (type 1 or type 2)
• Bariatric surgery
• Infectious diseases

Data analysis will be masked